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Message-ID: <20131217112452.GA3145@console-pimps.org> Date: Tue, 17 Dec 2013 11:24:52 +0000 From: Matt Fleming <matt@...sole-pimps.org> To: Dave Young <dyoung@...hat.com> Cc: linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org, x86@...nel.org, mjg59@...f.ucam.org, hpa@...or.com, James.Bottomley@...senPartnership.com, vgoyal@...hat.com, ebiederm@...ssion.com, horms@...ge.net.au, kexec@...ts.infradead.org, bp@...en8.de, greg@...ah.com, toshi.kani@...com, akpm@...ux-foundation.org, mingo@...nel.org, msalter@...hat.com, leif.lindholm@...aro.org Subject: Re: [PATCH v6 14/14] x86: kdebugfs do not use __va for getting setup_data virt addr On Tue, 17 Dec, at 02:53:46PM, Dave Young wrote: > On 12/17/13 at 02:24pm, Dave Young wrote: > > On 12/16/13 at 04:35pm, Matt Fleming wrote: > > > On Mon, 16 Dec, at 05:30:35PM, Dave Young wrote: > > > > kdump kernel will use memmap=exactmap kernel cmdline, but __va does not > > > > work in case memmap=exactmap, so let's always use ioremap_cache. > > > > > > > > Signed-off-by: Dave Young <dyoung@...hat.com> > > > > --- > > > > arch/x86/kernel/kdebugfs.c | 35 +++++++++++------------------------ > > > > 1 file changed, 11 insertions(+), 24 deletions(-) > > > > > > Dave, I've no idea why this change is necessary from the commit log. Is > > > it required for kexec to function on EFI? Why does __va() not work in > > > the memmap=exactmap case? > > > > > > > During previous kdump tests I saw panics while reading the setup_data in debugfs. > > I thought it is caused by some unmapped addresses. At that time I also reproduced > > it by booting the non-kexec kernel with memmap=exact. > > > > Since you are asking about this I'm testing it again but I seems can not > > reproduce this problem any more, it's weird. > > > > I should dug more about it and save the panic messages. > > > > So let's drop this patch for now, I will keep an eye on this and address it later > > if I can find the problem again. > > Reproduced it again in normal boot with memmap=exactmap, but I agree it's a corner > case, I remember I saw this in kdump kernel, but I still did not see it in today's > testing so I think move this issue out of this patch series is fine to me. Please include the following oops when you submit this patch again. > [ 0.359467] BUG: unable to handle kernel paging request at ffff8800d5592020 > [ 0.359472] IP: [<ffffffff817dbdbc>] arch_kdebugfs_init+0x11a/0x201 > [ 0.359474] PGD 316b067 PUD 37031063 PMD 0 > [ 0.359476] Oops: 0000 [#1] PREEMPT SMP > [ 0.359477] Modules linked in: > [ 0.359480] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3+ #65 > [ 0.359481] Hardware name: Hewlett-Packard HP Z420 Workstation/1589, BIOS J61 v03.15 05/09/2013 > [ 0.359482] task: ffff880037022000 ti: ffff880037188000 task.ti: ffff880037188000 > [ 0.359484] RIP: 0010:[<ffffffff817dbdbc>] [<ffffffff817dbdbc>] arch_kdebugfs_init+0x11a/0x201 > [ 0.359485] RSP: 0000:ffff880037189e30 EFLAGS: 00010286 > [ 0.359486] RAX: ffff8800372e30e0 RBX: ffff8800372e30e0 RCX: 0000000000000191 > [ 0.359486] RDX: 0000000000000000 RSI: ffffffff8168a39e RDI: ffff880037189e50 > [ 0.359487] RBP: ffff880037189e90 R08: ffff8800372e30e0 R09: 0000000000000000 > [ 0.359488] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88003640aea0 > [ 0.359489] R13: 00000000d5592018 R14: ffff88003640b200 R15: ffff8800d5592018 > [ 0.359490] FS: 0000000000000000(0000) GS:ffff880037480000(0000) knlGS:0000000000000000 > [ 0.359491] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.359491] CR2: ffff8800d5592020 CR3: 0000000002716000 CR4: 00000000000407e0 > [ 0.359492] Stack: > [ 0.359494] ffffffff817da6d5 ffff88003640b0e0 ffff88003640afc0 0000000000000004 > [ 0.359496] ffff880037180033 ffffffff8149d82d 00000000c9b42d58 ffffffff817dbca2 > [ 0.359498] 0000000000000000 00000000000000f3 0000000000000000 0000000000000000 > [ 0.359499] Call Trace: > [ 0.359502] [<ffffffff817da6d5>] ? boot_params_ksysfs_init+0x1ff/0x244 > [ 0.359507] [<ffffffff8149d82d>] ? mutex_unlock+0x9/0xb > [ 0.359508] [<ffffffff817dbca2>] ? topology_init+0x36/0x36 > [ 0.359512] [<ffffffff810002bf>] do_one_initcall+0xae/0x15b > [ 0.359515] [<ffffffff81078500>] ? parameq+0xb/0x1f > [ 0.359516] [<ffffffff81078770>] ? parse_args+0x25c/0x33a > [ 0.359519] [<ffffffff817d5ec6>] kernel_init_freeable+0x115/0x19b > [ 0.359521] [<ffffffff817d573d>] ? do_early_param+0x88/0x88 > [ 0.359523] [<ffffffff81489359>] ? rest_init+0xbd/0xbd > [ 0.359524] [<ffffffff81489362>] kernel_init+0x9/0xfa > [ 0.359527] [<ffffffff8149fd0c>] ret_from_fork+0x7c/0xb0 > [ 0.359528] [<ffffffff81489359>] ? rest_init+0xbd/0xbd > [ 0.359548] Code: ff 48 85 c0 48 89 c3 0f 84 b9 00 00 00 49 bf 00 00 00 00 00 88 ff ff 4c 89 28 8b 55 bc 48 8d 7d c0 4d 01 ef 48 c > [ 0.359549] RIP [<ffffffff817dbdbc>] arch_kdebugfs_init+0x11a/0x201 > [ 0.359550] RSP <ffff880037189e30> > [ 0.359550] CR2: ffff8800d5592020 > [ 0.359559] ---[ end trace d52b3fbe64a26115 ]--- > [ 0.621287] kworker/u8:0 (43) used greatest stack depth: 5232 bytes left > [ 0.628021] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 > [ 0.628021] -- Matt Fleming, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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